Be a good person and use the Shiekah Armor strategy in the future :P
Horse tip below (no real story spoiler below):
So the ice arrow strategy on horse is pretty effective. Just need to go behind them and spam A. Feels kind of messed up but I want a faster horse dang it!
How do you know someone's grinding for the Ancient Armor upgrades?
Answer: When they have enough materials to craft...76 Ancient Arrows. Need those Ancient Reactor Cores. Only 5 more to go, then every piece requires shooting star fragments >.<